Natural Alder (Saunawood) Cladding Board – T&G Profile – 89×15 mm – 2400 mm (8 ft.)

Natural Alder (Saunawood) Cladding Board

Line your sauna in Natural Alder and you get the one thing every sauna builder quietly worries about: timber that stays comfortable against bare skin even with the stove roaring. Because alder carries heat poorly, your bench backs and wall cladding warm gently rather than scorching, so you can lean back without flinching. These tongue-and-groove boards are milled from clean, knot-free European alder, kiln-dried and graded specifically for sauna use, and stocked in our yard for delivery across Ireland.

Why Alder?

European alder (Alnus glutinosa) earned its place in Nordic saunas for reasons that have little to do with looks, though the warm honey-to-russet tone certainly helps. Unlike pine or spruce, alder is effectively resin-free, so it won’t weep sticky pitch or spit hot droplets when the room comes up to temperature — the single most important reason it’s chosen for interiors people sit against undressed.

Its low density means it absorbs and holds very little heat, and its fine, even grain planes to a smooth surface that resists the splintering you’d get from coarser softwoods. The colour deepens attractively with every session, so the cladding tends to look better the more you use it.

Installation guidance

If you’ve fitted tongue-and-groove cladding before, this will feel familiar; if you haven’t, the profile does most of the work for you. Each board’s tongue slots into the groove of the last, self-aligning as you go, so a tidy, gap-free finish is well within reach for a confident DIYer.

Fix through the tongue using stainless steel pins or clips — ordinary nails corrode in the heat-and-humidity cycle and bleed rust marks. Leave a small expansion gap at floor and ceiling, keep a ventilated cavity behind the boards, and let the timber acclimatise in the room for a day or two before fixing so it settles at its working moisture content.

Finishing & maintenance

You have two good options with alder, and neither is wrong. The natural route — leaving the boards bare to darken gently with steam and time — is how most Finnish saunas are finished, and it asks nothing of you beyond letting the wood breathe. The treated route — wiping the cladding with a dedicated paraffin-based sauna oil — keeps the surface easier to clean and locks in the colour, and it’s worth doing on any board you’ll regularly touch. Most of our customers oil the bench-height boards and leave the upper walls natural.

One firm rule: never use ordinary varnish, lacquer, decking oil or exterior wood stain inside a sauna — they aren’t formulated for sustained high heat and will release fumes when warmed. Only ever use a finish made specifically for saunas (we stock the right one — just ask if you’re unsure which to pair with your boards). Whichever route you choose, clean with nothing more than a damp cloth and mild soap, then let the room ventilate fully so the timber dries between uses.